1. Field of the Invention
This application relates to motion estimation in display devices. In particular, this application relates to systems and methods for determining motion vectors for blocks of frame data.
2. Description of the Related Technology
In recent years, advancements in digital video processing have allowed video display manufacturers to produce systems which provide a more realistic viewing experience by enhancing raw digital video. Motion estimation algorithms are commonly used in providing enhanced video. For example, motion estimation algorithms are often utilized when performing de-interlacing of video, video format conversion, and frame rate conversion. Among the different types of motion estimation algorithms, block matching algorithms are often chosen for their superior trade-off between complexity (which is relatively low) and accuracy (which tends to be high). Block matching algorithms generally compare blocks in one frame of video in order to find a matching block from a different frame of video.
Recursive search techniques form one category of block matching algorithms. Recursive search block matching evaluates a limited set of candidate motion vectors to determine the best motion vector for each block of pixels in a video frame. Although the recursive search often performs well and is computationally inexpensive, these recursive algorithms tend not to be well-suited for cases of sudden or rapid change in motion of objects. Another category of block matching algorithms utilize non-recursive techniques. For example, the full-search algorithm (one of several types of non-recursive motion estimation techniques) evaluates all possible motion vector candidates in a pre-defined search range to determine the best matching block. While sudden changes in object motion do not typically impact the accuracy of the full-search (and other non-recursive) estimation results, these techniques are more sensitive to problems such as noise, low dynamic range, and multiple block matches. Accordingly, it would be useful to provide a motion estimation technique which alleviates all of the above-described shortcomings.